Intravascular infections Flashcards
transient bacteremia
clearance exceeds entry
source is local infection somewhere
continuous bacteremia
seeding exceeds clearance capacity
septicemia
clearance mechanisms subverted
in infective endocarditits is there a continuous concentration in the blood or does is go up and down?
continuous concentration of bacteria in the blood
what are the four endovascular infections
infective endocarditis
infected thrombus
mycotic aneurysm
infections of intravascular devices
predispositions of IE
congenital heart disease Rheumatic heart disease conditions leading to bacteremia IV drug abuse Hopitalization
prior to antibiotic era what was the fatality rate of IE?
100%
Pathogenesis of IE
- turbulent blood flow
- Endothelial cell activation
- Fibrin and platelet deposition
- Silent of clinical bacteremia seed sterile vegetations
- bacteria grow within fibrin vegetations
what is unique about the endocardium including valves, chordae, papillary muscle and atria that make them prime for immune evasion of bacteria?
they receive their nourishment from the blood stream and DO NOT have capillaries. Neutrophils require capillaries to get to infection site.
**Thus innate and acquired immune mechanisms are subverted.
observations of IE in vivo
bacteria imbedded within vegetations are impossible to entirely eradicate
*IE is characterized by unrestricted microbial replication within vegetations leading to in vivo bacterial colonies
Diagnosis: Duke Criteria
major findings
- continuous bacteremia
- target lesion on valve, supports or endocardium by (ECHO or new murmur)
Diagnosis: Duke Criteria
minor findings
fever predisposing heart condition IV drug user embolic phenomena immunological phenomena
signs of IE
tender Osler nodes
non tender Janeway lesions
Roth spot in eye
Conjunctival petechiae
Microbiology of IE
- staphylococci-S. aureus, coagulase neg staph spp.
- streptococci-viridans spp. and gamma strep
- Enterococci
- Gram negative bacilli
- Fungi
are more virulent and less virulent species going to cause IE?
less virulent
mostly Strep. mutans, where as S. pyogenes doesn’t causes much IE
clinical correlation
congestive heart failure stroke infarcts glomerulonephritis mycotic aneurysms abscesses(local or distant)
what dental procedures give the highest bacteremia values?
periodontal surgery 88%
extraction 60%
Brushing or irrigation device 40%
high risk adverse outcome from IE
- prosthetic heart valve or prosthetic material inserted for repair
- previous infective endocarditis
- congenital heart disease
- cardiac treatment patients who develop valvulopathy
how do you prevent IE
prophylactic antibiotics prior to procedures for those with: -prosthetic heart valves -previous IE -congenital heart diseases -heart Tx with valvulopathies IV or PO regimens at time of procedures
treatment of IE
IV therapy -bactericidal regimen length of treatment-2,4,6,8 wks test for antibiotic sensitivity Surgery
